The Microbiologist had a recent call from a worried colleague who had been contacted by an even more worried patient. The patient had just found out she was pregnant but was unaware of this while she was taking Doxycycline as malaria prophylaxis whilst on holiday. She had been on the internet and read that Doxycycline should never be given in pregnancy as it can do all sorts of horrible things to babies. The patient’s doctor had double checked in the British National Formulary (BNF) and sure enough Doxycycline was contraindicated in pregnancy. The Microbiologist confirmed what the BNF said; however exactly how big was the risk? The Microbiologist realised he didn’t actually know… time to start looking at the evidence and get back to the patient’s doctor as soon as possible.

Throughout my medical career I have been told never to give any tetracyclines, including Doxycycline, to pregnant women or children under 12 years of age. The reason given for this is that tetracyclines cause congenital abnormalities and problems with teeth and bone development in children and the developing fetus, as well as liver problems in the mother during pregnancy. But is this true? What is the evidence? Are there any circumstances where using Doxycycline is justified in these patients?